Rotary lift



H. MILEY ROTARY LIFT June 2, 1964 Filed March 3, 1959 INVENTOR HUNTER M/LE) 3,135,377 ROTARY LIFT Hunter Miley, Petrolia, Pa., assignor to Sonneborn Chemical and Refining Corporation, a corporation of Delaware Filed Mar. 3, 1959, Ser. No. 796,883 7 Claims. (Cl. 198214) This invention relates to a rotary lift apparatus and more. particularly to a rotary lift apparatus capable of efliciently elevating divided solid materials at higher temperatures..

' This invention is a continuation in part of my copending applications Serial No. 474,256, filed December 9, 1954 (Patent No. 2,929,689, dated March 22, 1960), Serial No. 538,988, filed October 6, 1955 (now Patent No. 2,897,054, dated July 28, 1959), and Serial No. 565,335, filed February 14, 1956, now abandoned.

Various oils, such as petroleum distillates or petroleum residues, overhead cuts derived from the distillation of coal tars, or hydrocarbon oils produced synthetically by hydrogenation or by the Fischer-Tropsch process are often purified to meet market specifications. In the course of purifying such oils, they are treated in liquid phase with strong sulfuric acid to remove those constituents which are most easily reacted with the acid. After suchtreatment, the reaction mass stratifies, with the treated hydrocarbon oil above and with a sludge layer below. Thesludge layer contains products of the reaction between the sulfuric acid and the hydrocarbons to- 'gether with unreacted sulfuric acid..

These sludges are found in varying degrees of fluidity, depending on the type and character of hydrocarbon reacted and the amount of residual sulfuric acid present. Various methods have been heretofore described for treatment of such sludges to recover the major part of the sulfur present in the form of sulfur dioxide. Among these are methods for the thermal decomposition of sludges, in the presence of coke particles in a closed cycle, wherein the sulfur dioxide is recovered and. a residue of coke remains. For" such treatmenttemperatures within the range of from about 30050 O. F. are often maintained inthe-apparatus. I p

Rotary lift means, including a rotatable worm in a tubular casing, have been employed heretofore for recycling thehot coke used in the above-described treatment bacli thruogh the closed system. However, in these cases, an ancillary pressure feed means Was usually necessary for the rotary lift means in order that the granular coke material could be forced upward by the rotating ,worm and not merely outward against the casing wall by reason of the centrifugal force. V

This forced feeding presented certain. difficulties and increased equipment costs, particularly where the rotary lift constituted a portion of a fixed apparatus such as that for moving granular material in a closed; cycle.

Rotary lift devices generally comprise a tubular casing in which a rotatable shaft carrying a worm means is disposed. The upper end of the shaft is seated or journaled in a bearing housing at the top of the casing and in devices having a closed bottom the lower end is seated in a similar bearing housing. Anciliary forced feeding means are provided adjacent the lower portion of the casing for conducting material into the rotary lift and outlet means are provided adjacent the upper portion of the casing for withdrawing material raised therethrough by'the worm. i w

A variation of the above construction is a device wherein the casing bottom is open and the lower section of the casing tapers inwardly and upwardly in funnel-like fashion. correspondingly, the portion of the worm means disposed in the tapered section of the casing is also A United States Patent OT tapered. In the case of granular materials, an ancillary rotary plow means attached to the lower end of the shaft is provided for elfecting the forced feed into the rotary lift bottom.

Dispensing devices having a tapered rotatable worm in a casing provided with an open bottom havebeen used where dense. viscous masses, having'the consistency of grease or butter, are concerned. The weight of the. mass itself contained in the receptacle surrounding the casing bottom effects the forced feeding into the dispenser. In

this case, the material being sticky Will hug the sides" of the container, thereby enabling the worm to maintain a grip'on the material. However, to achieve the lifting of material of such consistency, the worm must necessarily be operated at relatively low speeds. At such speeds, divided solid materials are not able to hug the wall of the vertical casing by means of centrifugal force, and this type of device, therefore, has very limited industrial application, i.e, conveyance of grease-like materials in a dispenser.

It is an object of the invention to provide an improved rotary lift construction which overcomes the disadvantages of conventional rotary lift devices, yet is efiicient 7 that the above mentioned disadvantages may be overi come and efficient and inexpensive operation achievedby providing an improved rotary lift construction wherein the lower portion of the tubular casing tapers or converges inwardly. and upwardly from a closed casing bottom in funnel-like configuration and the lower portion of the Worm is correspondignly outwardly flared or tapered. in this construction, the material. is fed into the casing at a point just above'the closed bottom solely by gravity feed and without the necessity for a separate ancillary forced feed means. 7

By combining the feature of a closed casing bottom with thatof the tapered lower casing and worm portions, granular materials may be efficiently conveyed upwardly upon rotation of the worm at sufiicient speed to force of the casing. No forced feed is required as the granular material acted upon by centrifugal force against the cas-v ing inner wall at the closed bottom tapered portion is upwardly. conveyed by the rotating worm moving relative thereto.

A particularly significant feature of the invention is the fact that no bearing is provided in the closed bottom surface of the casing for seating the lower end of the worm shaft. Where dealing with hot combustible solid materials, it will be apparent that in recycling the same in a system closed to air, as by means of a rotary lift, the construction of the invention is particularly advantageous. Furthermore, by omitting any bearingfor' the. lower end of the worm shaft, a suitably dimensioned shaft terminating at its lower end a slight distance above the casing bottom may freely expand and contract a slight" degree with changes in the temperature, a function which cannot be carried out where a' bearing is used.

For the same reason, no bearing is eniployed at the top end of the worm shaft. Instead, a sliding joint, such asisobtained by providing a carbon ring or sleeve sliding on a steel ring or sleeve, is used at the top end of the worm shaft which also permits expansion, yet effects a perfect seal with respect to the atmosphere at that point. The worm shaft is suitably mounted for rotation solely Patented June 2, 1964 changes in heat and corresponding expansion and contraction of the metal parts on contact with the hot material to be conveyed or by reason of heat exchange means provided on the casing exterior.

Referring to the drawing, shaft 1 is driven by any suitable means, such as a motor 2, mounted outside the rotary lift apparatus and connected to the shaft by means of shaft extension 11. Shaft ll carries Worm 3 which rotates in tubular casing 4, the inside diameter of which is slightly greater than the corresponding outside diameter of worm 3.

Worms of this general type operate in the same manner as horizontally oriented worm conveyors, with the exception that the speed of rotation in a rotary lift device generates suflicient centrifugal force to cause a granular material to hug the inside wall of the casing. In this way, the centrifugal force operates in the same manner as gravitational force operates in a horizontally oriented worm device. As a consequence, the material is carried progressively upwardly within the casing as the worm rotates.

' The upper end of casing 4 is provided with a discharge outlet 5, through which material which has been carried upwardly by operation of Worm 3 may be discharged. The lower end 6 of the casing 4 is provided with a gravity feed inlet '7, through which solid granular material may be supplied to the rotary lift formed by worm 3 in co action with casing 4. Casing 4, inlet '7, and outlet 5 are sealedfrom the atmosphere and inlet '7 and outlet 5 may be connected to adjacent conveying conduits or receiv-v ing chambers (not shown) also sealed from the atmosphere so as to maintain the sealed condition within casing 4.

Worm 3 and casing 4 are of uniform diameter through out the greater upper portion of their length in the conventional manner and any material supplied to this portion will be conducted upwardly due to centrifugal force directing the material outwardly against the casing wall and the coacting upward force of the rotating worm.

The smaller lower portion 8 of worm 3, however, is provided with a taper 9, whereby the lower portion of the worm is of greater diameter than the upper portion. Lower portion 8 of the worm tapers upwardly and inwardly to the diameter of'the upper portion. Correspondingly, the lower portion 6 of the casing wall must be formed with a greater diameter than the upper portion, to accommodate the increased diameter of the lower por-' tion 8 of the worm. The lower portion 6 of the casing is, therefore, formed with a taper 10' which tapers upwardly and inwardly at approximately the same angle as that subtended by the taper 9 at the lower end 8 of Worm 3. As a result, the worm will engage and lift granular material, even though supplied to inlet '7, under no positive pressure, since the bottom 12 of casing 4 seals the lower portion 8 against downward travel of the material and thereby forces said material into contact with the surrounding lower casing wall 6 and the portion of the Worm rotating thereat.

Hence, no ancillary means for supplying the material under pressure through the feed inlet 7 is necessary.

Shaft 1 is solely mounted for rotation by direct connection to independent drive means 2 above casing 4, the shaft extension 11 passing through the closed top end 13 of the casing at sealed sliding joint 14. This joint 14 is adas a bearing for the shaft. The carbon ring may be a graphite ring enclosing shaft extension 11 in tightly abutting relation for axial and rotational relative movement with respectto one another, so as to seal the parts from passage of air therebetween, the graphite serving as lubricant for the sliding joint. The lower end 15 of the shaft is constructed so that there is a slight clearance with the bottom 12 of the casing.- The worm and shaft, therefore, are mounted for rotation outside of and independently of the casing, and freely float in a tightly sealed chamber without the use of bearings.

Consequently, hot combustible granular materials, such as oily or highly volatile coke, may be efiiciently conveyed through the rotary lift device of the invention without vantageously preferably constructed of a carbon ring or I exposure to air orlother external combustible gases. Ex-

pansion of the shaft and worm, heated by the hot ma terial, may freely take place since a slight clearance be-- would require bearings and could only be made fluidtight or gas-tight, to theatmosphere, with great difiiculty in view of the :attendantexpansion that takes place with the exposure to 1 higher temperatures. Furthermore, it would be diflicult to jacket a bucket conveyor with hot gases or other heat transfer means, where thermal treatment is contemplated such as that involved with sulfurcontaining sludges. In this same connection, the above mentioned dispensmg devices employing a worm in a casing having an open bottom are inapplicable for the purposes for which a rotary lift is required.

Significantly, in order for a worm enclosed in a casing to be operable as a rotary lift, the worm must travel at a peripheral speed of rotation within the rangeof from substantially 5 to 15 feet per second whereas the pitch of the worm must be within the range of from substantially 8 to 16 inches. The foregoing ranges for the peripheral speed of rotation and the pitch of the worm are critical, and where the pitch andv peripheral speed of rotation are not within these ranges, rotary lift operation cannot be attained.

- Thus, while lower or higher worm speeds or other pitches may be provided ina worm device for some other purpose, such devices fail as rotary lifts in view of the criticality of the related speed of rotation and pitch of the worm where rotary lifts are concerned. A rotary lift must generate sufiicient centrifugal force by the speed of rotation of the worm to keep the material to be elevated outwardly disposed against the casing Wall while the pitch of the worm in cooperation therewith upwardly conveys the material.

What. is claimed is;

1. A rotary lift which comprises a substantially vertically extending worm means, said worm means having a pitch within the range of from 8 to 16 inches, a tubular casing means surroundingsaid worm means, said worm means having a lower portion of increased cross-sectional size tapering inwardly and upwardly to the diameter of the upper main portionof said worm means, said casing means having a lower portion of relatively greater diameter than the upper main portion thereof enclosing said tapered lower portion of said worm-means and also tapering inwardly and upwardly at approximately the same angle as the lower portion of said worm means, the top and bottom ends of said casing means being closed, a discharge outlet means adjacent the upper end of said casing means for withdrawing material therefrom and said casing means for feeding material thereinto, the lower end of said worm means being spaced a slight distance from the closed bottom end of said casing means, and means for rotating said worm means at a peripheral speed of rotation within the range of from 5 to feet per second.

2. A rotary lift which comprises a substantially vertically extending shaft, a worm means disposed on said shaft, said worm means having a pitch of from 8 to 16 inches, a tubular casing enclosing said worm means, said worm means haying a lower portion of increasing diameter tapering inwardly and upwardly to the diameter of the upper main portion of said worm means, said casing having a lower portion of relatively larger diameter than the upper main portion thereof enclosing said tapered lower portion of said worm means and correspondingly tapering inwardly and upwardly at approximately the same angle 'as the lower portion of said worm means, the top and bottom ends of said casing being closed, a discharge outlet adjacent the upper end of said casing for withdrawing material therefrom and a gravity feed inlet adjacent the lower portion of said casing for feeding material thereinto, the lower end of said shaft and said worm means terminating a slight distance above the closed bottom of said casing, the closed top end of said casing having an opening therein defined by a carbon ring, a shaft extension of the top end of said shaft upwardly projecting through said opening, said shaft extension and said ring forming a sliding joint sealed from the atmosphere, and means connected to said shaft extension for freely supporting said shaft independently of said casing and for rotating said shaft at a peripheral speed of rotation within the range of from 5 to 15 feet per second, suflicient to centrifugally force material to hug the inside wall of said tubular casing.

3. In a rotary lift for elevating granular material, including a, substantially vertically extending worm, a tubular casing surrounding said worm, means for rotating said worm and a discharge outlet adjacent the upper end of said casing, the improvement which comprises said worm having a pitch of from 8 to 16 inches and a lower portion of increased diameter tapering inwardly and upwardly to the diameter of the upper main portion of said worm, said casing having a lower portion of relatively larger diameter than the upper main portion thereof enclosing said tapered lower portion of said worm and correspondingly tapering inwardly and upwardly at approximately the same angle as the lower portion of said worm, the top and bottom ends of said casing being closed, the lower end of said worm terminating a slight distance above the closed bottom of said casing, a gravity feed inlet adjacent the lower portion of said casing for feeding granular material thereinto, said means for rotating said worm including means for freely rotatably supporting said worm in said casing independently of said casing at a peripheral speed of rotation within the range of from 5 to 15 feet per second, sufficient to centrifugally force granular material to hug the inside wall of said tubular casing.

4. The improvement of claim 3 wherein the interior of said casing is sealed from the atmosphere.

5. The improvement of claim 3 wherein said worm is provided with a shaft extension on its upper end which projects through said closed top end of the casing through means defining a sliding joint sealed from the atmosphere, said shaft extension being connected to said rotating means.

6. The improvement of claim 5 wherein said means defining a slidable joint includes a carbon ring of suitable dimensions through which said shaft extension projects in sealed condition.

7. .A rotary lift apparatus for elevating granular material which comprises a substantially vertically extending worm having a pitch within the range of from 8 to 16 inches, a tubular casing surrounding said worm, means for independently suspending said worm in said casing and for rotating said worm at a peripheral speed of rotation within the range of from 5 to 15 feet per second, sufiicient to centrifugally force granular material to hug the inside wall of said casing, a discharge outlet adjacent the upper end of said casing and a gravity feed inlet adjacent the lower end of said casing, said worm having a lower portion of increased cross-sectional size tapering inwardly and upwardly to the diameter of the main portion of said worm, said casing having a lower portion with a closed bottom and of relatively greater diameter than the upper portion thereof enclosing said tapered lower portion of said worm and also tapering inwardly and upwardly at approximately the same angle as the lower portion of said worm, said gravity feed inlet adjacent the lower end of said casing being arranged for feeding granular material into the lower closed portion of said casing.

References Cited in the file of this patent UNITED STATES PATENTS 825,905 Hellyer July 17, 1906 1,778,589 Eerkes Oct. 14, 1930 2,917,329 Laser Dec. 15, 1959 2,937,039 Santapa May 17, 1960 FOREIGN PATENTS 227,530 Switzerland Sept. 16, 1943 740,308 Great Britain Nov. 9, 1955 

1. A ROTARY LIFT WHICH COMPRISES A SUBSTANTIALLY VERTICALLY EXTENDING WORM MEANS, SAID WORM MEANS HAVING A PITCH WITHIN THE RANGE OF FROM 8 TO 16 INCHES, A TUBULAR CASING MEANS SURROUNDING SAID WORM MEANS, SAID WORM MEANS HAVING A LOWER PORTION OF INCREASED CROSS-SECTIONAL SIZE TAPERING INWARDLY AND UPWARDLY TO THE DIAMETER OF THE UPPER MAIN PORTION OF SAID WORM MEANS, SAID CASING MEANS HAVING A LOWER PORTION OF RELATIVELY GREATER DIAMETER THAN THE UPPER MAIN PORTION THEREOF ENCLOSING SAID TAPERED LOWER PORTION OF SAID WORM MEANS AND ALSO TAPERING INWARDLY AND UPWARDLY AT APPROXIMATELY THE SAME ANGLE AS THE LOWER PORTION OF SAID WORM MEANS, THE TOP AND BOTTOM ENDS OF SAID CASING MEANS BEING CLOSED, A DISCHARGE OUTLET MEANS ADJACENT THE UPPER END OF SAID CASING MEANS FOR WITHDRAWING MATERIAL THEREFROM AND A GRAVITY FEED INLET MEANS ADJACENT THE LOWER PORTION OF SAID CASING MEANS FOR FEEDING MATERIAL THEREINTO, THE LOWER END OF SAID WORM MEANS BEING SPACED A SLIGHT DISTANCE FROM THE CLOSED BOTTOM END OF SAID CASING MEANS, AND MEANS FOR ROTATING SAID WORM MEANS AT A PERIPHERAL SPEED OF ROTATION WITHIN THE RANGE OF FROM 5 TO 15 FEET PER SECOND. 